how to design gain equalizer?

[YiPing]

Gain equalizers are passive microwave components,
which are designed to compensate for a variety of
insertion loss slopes and irregularities to provide a flat
output response.
How to design it?

 

[sergio mariotti]

I try to describe by text the schematic.
Problem: Design an equalizer that attenuate more dB at lower frequency.

Solution:
Desing a TT (Pi-Greek) atteuator made by pure resistors.
Place an inductor (L) connected series to each shunt resistors.
Place a capacitor parallel to the series resistor.

Working philosophy:
At lower freq. The C is open and L is a short, so the circuit work as attenuator.
At higher freq. The C is a short circuit and the L are open circuited, so the circuit work as a 0 dB attenuator.

For the value, use a simulator, but remember: everytime take in account parasitic, subtle, invisible effect like parasitic inductance to GND and open end effect on lines etc.